Page 115 - IM_FL_Geometry_Print Sample

price (dollars)
angle (radians)
radius (cm)
slice 1
4
1.5
20
slice 2
3.75
22
slice 3
4
1
25
slice 4
1.75
23
slice 5
4
0.8
28
slice 6
4.50
30
slice 7
3.50
18
slice 8
2.75
15
Help Elena decide which slices to try by ordering them according to which are the best deals.
Student Response
The best deals in descending order of square centimeters per dollar are:
1. Slice 8 at 85.7 square centimeters per dollar.
2. Slice 4 at 79.1 square centimeters per dollar.
3. Slice 6 at 78.5 square centimeters per dollar.
4. Slice 5 at 78.4 square centimeters per dollar.
5. Slice 3 at 78.1 square centimeters per dollar.
6. Slice 1 at 75 square centimeters per dollar.
7. Slice 7 at 72.7 square centimeters per dollar.
8. Slice 2 at 67.6 square centimeters per dollar. The same order can be obtained by listing dollars per square centimeter in ascending order.
Activity Synthesis
Ask each group to explain their calculations and demonstrate how to record those calculations in the spreadsheet. Ask students to explain the process for nding the area per dollar of a slice of pizza more generally if the slice of pizza has a central angle of radians, a radius of cm, and a
price of dollars. This should lead to an expression for the amount of pizza per dollar for a slice.
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Teacher Guide